Scrubbing (moving rapidly) in the timeline or changing the offset frame value of an Input Image node (containing video media), causes Blender to lose frames of the source media. To fix this I have to delete the input node and reload the source media. Creating a new datablock as the previous one becomes corrupted with black frames.

This happens with a h264 QT file from a Canon DSLR camera.

Scrubbing the same clip in the Movie Clip editor (tracker) does not fail.
Scrubbing the same clip in the VSE does not fail. Using both Movie strip or Clip Strip.

Win XP b2.63 r47443

I cannot embed footage and they are to large to submit here. I will try to link some.

Well, that's because clip editor and sequencer are doing a bit smarter things using proxies and there're several tools imlemented there to make them working nice. This wasn't actually finished for image datablocks. It might be improved further, but wouldn't actually consider this is a bug.

You might do one of this two things:
- Preprocess your movie using external application making sure all index frames are set correct and that constant framefrate is used
- Use Movie Clip input and if it's needed generate proxies for movie. I'd say it's more reliable way.